Supersensitized silver halide emulsions containing a meso-alkoxyl substituted carbocyanine and a 2,2&#39; cyanine



Patented Oct. 9, 1951 SUPERSENSITIZED' SILVER HALIDE EMUL- SIONS CONTAINING A MESO-ALKOXYL SUBSTITUTED CARBOCY ANINE AND A 2,2

CYANINE Marcel Adam Schouwenaars, Edegem-Antwerp, Leo Arnold. Van de Straete, Mortsel-Antwerp, and Oscar Hendrik Van den Broele, Wilrijk- Antwerp, Belgium, assignors to Gevaert Photo- Producten N. V., Mortsel-Antwerp, Belgium, a

company of Belgium No Drawing. Application July 21, 1947, Serial No. 762,536. In Germany December 31, 1943 Section 1, P'ublic as 690, August 8, 1946 Patent expires December 31, 1963 2 Claims.

This invention relates to halide emulsions the spectral sensitivity of which has been modified by means of symmetrical or unsymmetrical carbocyanines containing an alkoxyl or substituted alkoxyl group at the central carbon atom of the trimethyne chain.

According to the French Patent No. 742,639 it has been proposed to sensitize photographic emulsions by means of compounds considered as meso-alkoxyl substituted carbocyanines and manufactured by condensation of quaternary cycloammonium salts, which contain a reactive methyl group, with ,tetraalkyl orthocarbonic esters in the presence of piperidine or non-volatile alkalies as condensation agent. Carbocyaphotographic silver I nine dyestufis produced by the same process are described as suitable sensitizers of photographic emulsions by Piprianow, Ssytnik and Ssytsch in Chem. Zentr. I, 1936, page 4654, who also agree as to the formation of meso-alkoxyl substituted carbo-cyanines during the condensation. This assumption, however, has been found to be wrong. As explained hereinafter, no meso-alkoxyl substituted carbocyanines but the known meso-alkyl substituted carbocyanines are formed when using tetraalkyl orthocarbonic esters in the presence by incorporating therein a heretofore unknown meso-alkoxyl carbocyanine dyestuff.

A further object of our present invention is to provide photographic single or. multi-layer material comprising a light-sensitive silver halide emulsion layer containing a heretofore unknown carbocyanine dyestufi.

Further objects will become apparent from the following description.

We have found that these objects are accomplished by incorporatil lg in a photographic silver 7'. f

halide emulsionone of the ineso-alkoxyl substituted carbocyanines which have an unexpected strong capacity for sensitizing photographic emulsions. These meso-alkoxyl substituted carbocyanines correspond to the following formula: 0R e 4' wherein Y and Z are the same or difiernt nonmetallic atoms necessary to complete a 5- or '6-membered N-containing heterocyclic nucleus including a substituted nucleus and a nucleus fused to another nucleus or to a ring system, B is alkyl, substituted alkyl; R, R are the same or different alkyl, substituted alkyl, aryl or aralkyl groups, and X is an acid residue.

These carbocyanines are obtained by causing 2 (beta methyl beta alkoxyl vinyl) cycloammonium salts of the general formula:

to react, as described in the copending application Ser. No. 755,228, filed June 17, 1947, by Leo Arnold Van de Straete et al., now Patent No. 2,557,806, with a heterocyclic quaternary salt usable for cyanine condensations and containing an atom group capable of reacting with the CH3 group of the 2-(beta methyl-beta-alkoxylvinyl) -cycloammonium salts.

Compared with the corresponding alkyl substituted dyestuffs, the meso-alkoxyl dyestuffs of our invention obtained in this way possess an absorption maximum which is shifted towards the short wave. region. This means thatgthe meso-alkoxyl carbocyanines may be used-j for green or blue sensitized photographic emulsions whereas the corresponding carbocyanines bearing in meso-position the known substituents ar panchromatic sensitizers; l n.

Some specific examples illustrating our invention are given hereinafter.

Ezrample 1 A meso-alkoxyl carbocyanine usable as blue sensitizer of the probable formula:

has a sensitizing maximum at 505 m the maximum of the corresponding meso-methyl carbocyanine being at 560 m Example 2 A blue sensitizer oi the probable formula:

4 T OCH; O-CH=C-CH=C N/ \N Br- 0211 32115 has a sensitizing maximum at 520 m the maximum of the corresponding mesa-methyl carbocyanine being at 575 m The following examples show alkoxyl substituted carbocyanines suitable for orthochromatic sensitizing of silver halide emulsions.

Example 3 The sensitizer of the formula:

o-oH=coH=o Br N N 41H: ('33:

has a sensitizing maximum at 520 m the maximum of the corresponding meso-methyl carbocyanine being at 590 m Example 4 The sensitizer of the formula:

has a sensitizing maximum at 530 m the maximum of the corresponding meso-methyl carbocyanine being at 600 m Example 5 The sensitizer of the formula:

has a sensitizing maximum at 510 m.

T 0 cam c-oH=t:-cH=o I- N N Example 6 The sensitizer of the formula:

has a sensitizing maximum at 520 m the maximum of the corresponding meso-ethyl carbocyanine being at 630 m For panchromatic sensitizing carbocyanine dyestuffs may be used which'contain nuclei, such as quinoline and naphthothiazole which cause these dyes to absorb longer wave lengths and whereby some of these dyestufls spontaneously cause a second sensitizing maximum.

Example 7 The sensitizer of the formula:

on: --on NIT has a sensitizing maximum at 645 to 650 m (second maximum).

' The alkoxyl substituted carbocyanines according to the present invention are also most suitable for use in combination with other s'ensitiz'ers whereby often a strong sensitizing effect is obtained. In this respect the supersensitizing, for instance, of pseudocyanines is especially important. The dyestufis used until now for the supersensitizing of pseudocyanines in the ortho region generally had a too high red-sensitiveness whereas the dyestufis without this disadvantage are inferior supersensitizers. The compounds according to this invention overcome all of these disadvantages.

Example 8 An excellent orthochromatic supersensitizing effect is obtained by combining the dyestufi of Example 3 with the known quinopseudocyanine ethyl bromide.

It will be apparent that the above examples are illustrative of a few adaptations of the in- 2,570,494 5 symmetrical and unsymmetrical oarbooyanines REFERENCES CITED of the following general formula:

file of this patent:

j X- 5 UNITED STATES PATENTS I Number Name Date 2,066,966 Dieterle et a1. Jan. 5, 1937 wherein Y and Z are non-metallic atoms neces- 2.156.464 Schulz May 2, 1939 sary to complete a; heterocyclic N-containing "2,166,938 Carroll July 25, 1939 nucleus, R, R and R" are alkyl, and X is an acid residue, and a. 2,2'-cya.nine in order to obtain OR PATENTS a supersensitizing effect. Number Country t MARCEL SCHOUWENAARS- 42,245 France Mar. 21, 1933 LEO ARNOLD VAN STRAETE- 42,256 France Mar. 28, 1933 OSCAR HENDRIK VAN DEN BROELE. 15

The following references are of record in the 

2. A LIGHT-SENSITIVE PHOTOGRAPHIC SILVER HALIDE EMULSION CONTAINING A DYESTUFF SELECTED FROM THE GROUP CONSISTING OF MESO-ALKOXYL SUBSTITUTED SYMMETRICAL AND UNSYMMETRICAL CARBOCYANINES OF THE FOLLOWING GENERAL FORMULA: 